This change will halve our block time (from 2s to 1s), and make us an Ethereum rollup, with proof-based bridging and data availability on Ethereum. This will slightly increase the cost of transactions, and extend the time required for native withdrawals to around 7 days (though faster liquidity bridges will likely continue to dominate bridging volume).
Currently, Immutable Chain has a native bridge based on an external cross-chain messaging network (Axelar). This chain has already:
- Processed almost 250 million transactions
- Been used by more than 18 million wallets, including over 6 million Immutable Passport users (one of the most widely used smart contract wallets in the world)
- Supported hundreds of games (either live or in development)
This migration will allow us to replace the existing bridge with directly verified withdrawals against state commitments posted to Ethereum. We will begin with permissioned fault proofs, before introducing zk-validity proofs. Using OP Stack will also enable us to adopt protocol upgrades, EVM upgrades, and security patches more quickly.
We are targeting the middle of 2027 for this migration. The migration will require a brief outage in block production (several hours), and we will be providing substantial advance notice once this date is confirmed.
To understand the exact modifications and any changes required, please see our documentation for apps or infrastructure providers for more details.
Additionally, as part of this migration, we will be deprecating the current Immutable testnet for game usage by the end of 2026. Gas on Immutable Chain is extremely cheap, and the lack of third-party integrations has made our public testnet suboptimal for actually testing complex game flows. Most games are running their testing flows against their own local chains, or just testing using the production chain. The primary advantage of this testnet was to allow us to test upcoming chain releases: we will now receive that benefit from the OP ecosystem.
Please contact your Immutable account manager for any support you may require during this process.
Alex Connolly, CTO
Ermyas Abebe, Head of Blockchain
